I live in Vermont in a Ranch with a walkout basement. Since half of my foundation is exposed to the exterior anyway it's not a big deal for me to insulate the outside of my foundation.

I looked up what I need, 4" foam don't overlap gaps, tar paper, flashing, and they said a drain pipe and show how it should go. Do I need this drain pipe? I'm at the top of a hill, on sandy soil, and I've never had water issues in my basement even when we lost a bridge from so much flooding. My basement isn't painted with the waterproof black, it's just exposed concrete.

So, if I've never had water issues in my basement, I'm at the top of a hill, and I'm on sandy soil should I do the extra work & effort to put this drain pipe in also?

The answer is NO for several reasons:

-Your state has no such code requirement
-If your house drains well naturally there is no real need for a french drain system
-You can create same effect with a trench filled with washed crushed stone withoit the drain tile...and it appears your naturally sandy soil and natural grade at the top of the hill is providing that anyhow.

It won't hurt to install french drains, but you likley don't need to.

Although Vermont is not known for heavy termite problems, it should be noted that the use of rigid foam insulation sheets in the exterior of foundations should be limited or prohibitied in areas of known termite infestations.

The foam board provide protected keyways by which termites can access the main structure and the foam prevents observing the existence of termite tunnels.

Unless you are in extreme southern Vermont, you should have no worries regarding termites.

Thank you.

I am in extremely Southern VT. Although I've never seen a termite (houses tend to get infested with Carpenter Ants here instead) how does one insulate the external basement foundation and prevent the risk of termites?

It would be so much work for me to insulate the inside of my basement because it's already finished and has an inlaw kitchen.

Thanks!

Mark:
The only way to assure you do not develop hidden termite problems when using rigid foam against the the outside foundation area is to pretreat the foundation for termites by an approved pest control company.

Southern Vermont termite infestations are slight, but do occur.

Thanks homebild, you helped me a lot and did a good job.

Mitch:

Drain tiles need to be placed within about 1 foot of the footer all the way around so you will need to install elbows to have the drains conform to the footprint of the foundation. The tiles need to be placed in at least 12 inches of crushed stone.

Second, your plan for the floor under your basement and crawlspace slab is fine placing crushed stone, then polyethylene then foam insulation with concrete on top of that.

Just do not forget that your state code requires not only your basement walls to be insulated but your crawlspace walls as well.

Depending on your county in Washington, you will need to have at least R-9 to R-11 on the basement walls and between R-17 and R-20 on the crawlspace walls.